Steve Serby

Steve Serby

NFL

Snoopy Bowl boils down to Eli Manning vs. Rex Ryan

Eli Manning will stagger into JetLife Stadium on Friday night more vulnerable than he ever has been since Jets coach Rex Ryan barged into town in 2009 with his grandiose ambition to make all Giants little brothers to all Jets. Manning, Big Brother of New York football, won his second Super Bowl in 2012 anyway.

The main plot line for this Snoopy Bowl was supposed to be Geno Smith vs. Michael Vick more than Manning vs. Manning. But Vick never was offered a fair fight, while Manning wages a furious battle to execute the new West Coast offense that was supposed to reenergize him but has teased and tormented him instead.

So the Snoopy Bowl presents, in so many ways, Eli vs. Rex: the two-time Super Bowl MVP who desperately is seeking a psychological boost and a chance for Big Blue Nation to move its collective finger away from the panic button vs. the man who will stop at no end to trumpet and validate his beloved defense and win a game he has been known to confuse with the Super Bowl.

It is safe to say Rex didn’t come here to kiss Eli’s rings. He lives to welcome all quarterbacks enduring growing pains to his House of Pain. He is dangerous whenever he smells blood, and the blood he smells is Eli’s.

“It’s anybody’s guess what we’re seeing out [the Giants] offensively in preseason, ’cause it’s embarrassing, and they know it is, too,” NFL Network analyst Charley Casserly told The Post. “But is this simply they’re working on one thing in practice and another in a game? Or is this a disconnect on a system? You sometimes don’t know until the regular season starts.

“This just looks worse than it should look. I’m just watching Eli, the fundamentals bother me. His footwork isn’t good — he’s all over the place with his feet. He seems to be muscling the ball — it’s not natural to him when he’s throwing it. And maybe I didn’t notice that in the past, but it seems to be more in preseason than I’ve seen in the past, so I can’t answer why, ’cause I’m not there, and I don’t think anybody who isn’t there can really answer it either.”

Casserly was asked why Manning would be muscling the ball.

“I don’t know,” he said. “When you see that, you say to yourself, ‘OK, does this guy got a shoulder problem?’ And maybe he’s always done this. I haven’t seen it in the past. It just seems to me it’s something I’m seeing. When I say muscling the ball, the shoulder seems to be following through more on it, it’s not so much the flick of the wrist. … I don’t know if it’s anything at all.”

Manning and his offensive teammates are learning a new language at the same time. Even acknowledging that rookie offensive coordinator Ben McAdoo isn’t showing his hand, it’s Greek to them to date.

“If the issue is terminology and getting everybody on the same page, that comes onto the coach,” Casserly said. “As far as learning a new system … maybe this is a bad example, but Chip Kelly comes into Philadelphia with a radically new system, and Nick Foles with very limited experience, and the guy has an off-the-chart year. It’s not unheard of for these things to happen and it comes in and it’s smooth. This one’s rougher than I’ve seen with them.”

The fact coach Tom Coughlin’s offensive line remains in an experimental flux has complicated life for Manning, who spent much of last season flinching under siege. Victor Cruz hasn’t caught a pass and first-round draft pick Odell Beckham Jr. hasn’t played a down. The tight ends and receiver Rueben Randle have been underwhelming. Manning hasn’t had the luxury of throwing to towering free-agent rookie Corey Washington, who catches TDs from backups every week.

“As far as smarts, and as far as getting it, he’ll understand it, but the other moving parts have to come along, too,” NFL Network analyst Steve Mariucci said. “Everybody’s gotta memorize what they do. And then the other part of it is being able to execute it with some precision, and that takes time. It’s not just the quarterback trying to master it.

“I think their offense will get better as the season progresses. It’s gonna be over the course of a season. They’re not gonna be hitting on all eight cylinders Day 1. The way we practice now, with the new collective bargaining agreement, there simply isn’t enough practice time and practices for everybody to be really on the same page. So I think it’s just gonna be a gradual thing.”

Manning and his offense, in dire need of positive reinforcement, should welcome the sight of the depleted, embattled Jets cornerbacks. Every silver lining has a cloud, however: Muhammad Wilkerson and Sheldon Richardson will try to suffocate Manning so he can’t go over the top on, say, Antonio Allen, while first-round safety Calvin Pryor will be an omnipresent heat-seeking search-and-destroy missile for any Giant who ventures into his Bermuda Triangle.

A howling green-and-white funhouse will be waiting to greet (taunt) Manning. How’s this for irony: Geno Smith knows Marty Mornhinweg’s playbook considerably better than Eli Manning knows McAdoo’s.